Understanding what I need is easy; finding the correct formula perhaps
not so much

Say that my range, in C11:C100 , contains some cells that are not
empty (non blank). Say that in B11:B100 I have the series 1, 2, 3...
and so on until 90.

Imagine that the first cells in my range B11:C100 contain

1 (blank)
2 (blank)
3 AB
4 (blank)
5 ZM
6 (blank)
7 HJ
....

Now, if in cell M11 I input the value 3, that means that I need to
find the 3rd non blank cell in my C column range. That is, my function
should return 7.

I can work with array funsctions, but I would not like to work with
intermediate calculations in additional cells.

Is it impossible what I am looking for?

Thank you for any help that you may supply